JP2014070182A - Adhesive sheet for manufacturing semiconductor device, semiconductor device and method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet for manufacturing a semiconductor device capable of firmly fixing a semiconductor wafer on a pedestal, as well as easily separating the pedestal from the semiconductor wafer.SOLUTION: An adhesive sheet for manufacturing a semiconductor device is used for fixing a semiconductor wafer on a pedestal, and includes a first adhesive layer and a second layer with adhesive strength lower than the first adhesive layer. At least a peripheral part of the adhesive sheet for manufacturing a semiconductor device is formed by the first adhesive layer.

Description

The present invention relates to an adhesive sheet for manufacturing a semiconductor device, a semiconductor device, and a method for manufacturing the semiconductor device.

Conventionally, in a semiconductor device manufacturing process, after a semiconductor wafer is temporarily fixed on a pedestal, a predetermined process such as back grinding is performed on the semiconductor wafer, and then the pedestal is separated from the semiconductor wafer. There is. In such a process, it is important that the pedestal can be easily separated from the semiconductor wafer.

As a method for temporarily fixing a semiconductor wafer on a pedestal, it is known to use a liquid adhesive. The liquid adhesive is applied to the semiconductor wafer or the pedestal by spin coating.

In Patent Document 1, a device wafer as a first substrate and a carrier substrate as a second substrate are pressure-bonded through a filling layer that does not form a strong adhesive bond, and a bonding material is filled into the periphery of the filling layer. A method of forming an edge bond by curing and bonding the first substrate and the second substrate is disclosed.

Patent Document 2 discloses a bonding composition layer containing a compound selected from the group consisting of oligomers and polymers, selected from the group consisting of polymers and oligomers of imides, amidoimides and amidoimide-siloxanes. A method of joining the first substrate and the second substrate via the above is disclosed.

Special table 2011-510518 gazette Special table 2010-53385 gazette

The filling layer described in Patent Document 1 and the bonding composition layer described in Patent Document 2 are applied by spin coating or the like. However, if a layer with a thickness of 10 μm or more necessary for adhesion is formed by coating, the coated surface is generally rough, the unevenness followability is poor, the desired adhesive force cannot be obtained, and the semiconductor wafer is sufficiently fixed to the pedestal. There are cases where it is not possible.

In addition, when applying by spin coating, there is a problem that most of the material is wasted. In addition, since the material has a high viscosity for bonding, labor is required to remove the dirt on the spin coater.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an adhesive sheet for manufacturing a semiconductor device that can firmly fix a semiconductor wafer to a pedestal and easily separate the pedestal from the semiconductor wafer. Another object of the present invention is to provide a semiconductor device using the adhesive sheet for manufacturing a semiconductor device and a method for manufacturing the semiconductor device.

The present inventor has found that the above-mentioned problems can be solved by adopting the following configuration, and has completed the present invention.

That is, the present invention is an adhesive sheet for manufacturing a semiconductor device used for fixing a semiconductor wafer to a pedestal, and includes a first adhesive layer and a second layer having an adhesive force lower than that of the first adhesive layer. And at least a peripheral part of the adhesive sheet for manufacturing a semiconductor device is formed by the first adhesive layer.

Since the adhesive sheet is in the form of a sheet, the surface can be formed more uniformly than when the adhesive layer is formed by spin coating. Furthermore, the material is not wasted like spin coating. Moreover, since it is a sheet form, it can be used simply.

Moreover, the peripheral part of the said adhesive sheet is formed of the said 1st adhesive bond layer. Since the first adhesive layer having a higher adhesive force than the second layer is present in the peripheral portion, the semiconductor wafer can be firmly fixed to the pedestal in this portion.
Moreover, since it has not only the 1st adhesive layer but the 2nd layer whose adhesive force is lower than the 1st adhesive layer, if even the adhesive force of the 1st adhesive layer is lowered, it will be removed from the semiconductor wafer by external force. The pedestal can be easily separated.
As a method for reducing the adhesive strength of the first adhesive layer, a method of reducing the adhesive strength by dissolving the first adhesive layer with a solvent, a physical cutting with a cutter, laser or the like in the first adhesive layer. Examples thereof include a method for reducing the adhesive strength by heating, a method for forming the first adhesive layer with a material whose adhesive strength decreases by heating, and a method for decreasing the adhesive strength by heating. Since the first adhesive layer is formed in the peripheral portion of the adhesive sheet, the first adhesive layer is dissolved by a solvent, or physically cut by a cutter or a laser, It is easy to reduce the adhesive force of one adhesive layer, and to easily separate the pedestal from the semiconductor wafer.

In the present invention, the adhesive strength of the first adhesive layer and the adhesive strength of the second layer refer to 90 ° peel peel force on a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel rate of 300 mm / min. . In addition, when a 1st adhesive bond layer is what adhere | attaches by performing imidation, thermosetting, etc., the 90 degree peel peel force in the state (for example, after imidation or after thermosetting) fixed to the silicon wafer. Say. When the second layer is bonded by imidization, thermosetting, or the like, it means 90 ° peel peeling force in a state of being fixed to a silicon wafer (for example, after imidization or after thermosetting). Specifically, it can be measured by the method described in the examples.

In the adhesive sheet, it is preferable that a central portion inside the peripheral portion is formed by stacking the first adhesive layer and the second layer. According to the said structure, a semiconductor wafer or a base can be firmly fixed in the surface which only the 1st adhesive bond layer has exposed. In addition, since the central portion is formed by stacking the first adhesive layer and the second layer, the central portion is relatively bonded to the peripheral portion formed only by the first adhesive layer. Power is low. Therefore, the base can be easily separated from the semiconductor wafer by an external force if at least the adhesive strength of the peripheral portion is reduced. Further, when the second layer is in contact with the pedestal, the adhesive sheet is easily peeled off from the pedestal, the adhesive residue is small, and the pedestal is easy to reuse.

In the adhesive sheet, it is also preferable that a central portion inside the peripheral portion is formed by the second layer. According to the said structure, since the center part is formed with the 2nd layer, if the adhesive force of a 1st adhesive bond layer is reduced, a base can be easily isolate | separated from a semiconductor wafer by external force. Further, since the second layer is in contact with the pedestal, the adhesive sheet is easily peeled off from the pedestal, the adhesive residue is small, and the pedestal is easy to reuse.

It is preferable that a third layer having a lower adhesive force than the first adhesive layer is formed over the peripheral portion and the central portion. When the surface on which the third layer having a lower adhesive strength than the first adhesive layer is exposed is attached to the semiconductor wafer, the adhesive sheet can be easily peeled from the semiconductor wafer. Further, the adhesive residue on the semiconductor wafer can be eliminated, and the semiconductor wafer cleaning step can be omitted.

The present invention also relates to a semiconductor device obtained using the adhesive sheet for manufacturing a semiconductor device.

The present invention also relates to a method for manufacturing a semiconductor device, comprising: a step of fixing a semiconductor wafer to a pedestal using the adhesive sheet for manufacturing a semiconductor device; and a step of separating the pedestal from the semiconductor wafer.

According to the present invention, the semiconductor wafer can be firmly fixed to the pedestal, and the pedestal can be easily separated from the semiconductor wafer.

2 is a schematic cross-sectional view of an adhesive sheet according to Embodiment 1. FIG. 2 is a plan view of the adhesive sheet of Embodiment 1. FIG. It is a cross-sectional schematic diagram of the adhesive sheet of Embodiment 2. It is a top view of the adhesive sheet of Embodiment 2. It is a cross-sectional schematic diagram of an adhesive sheet provided with a 3rd layer. It is a cross-sectional schematic diagram of an adhesive sheet provided with a 3rd layer. It is a schematic diagram which shows a mode that the semiconductor wafer was fixed to the base using the adhesive sheet of Embodiment 1. FIG.

[Adhesive sheet]
The adhesive sheet for manufacturing a semiconductor device of the present invention has a first adhesive layer and a second layer having an adhesive force lower than that of the first adhesive layer, and at least a peripheral portion of the adhesive sheet for manufacturing a semiconductor device is It is formed by the first adhesive layer.

Hereinafter, the adhesive sheet of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of the adhesive sheet 5 of the first embodiment. As shown in FIG. 1, the adhesive sheet 5 has a peripheral portion 54 formed of a first adhesive layer 50, and a central portion 53 inside the peripheral portion 54 has a first adhesive layer 50 and a second adhesive layer 50. It is formed by stacking with the layer 51. That is, the adhesive sheet 5 includes a second layer 51 and a first adhesive layer 50 that is laminated on the second layer 51 in such a manner as to cover the upper surface and side surfaces of the second layer 51. The adhesive force of the second layer 51 is lower than the adhesive force of the first adhesive layer 50.

The peripheral portion 54 of the adhesive sheet 5 is formed by the first adhesive layer 50. Since the first adhesive layer 50 having higher adhesive strength than the second layer 51 is present in the peripheral portion 54, the semiconductor wafer can be firmly fixed to the pedestal in this portion.
Moreover, since it has not only the 1st adhesive bond layer 50 but the 2nd layer 51 whose adhesive force is lower than the 1st adhesive bond layer 50, if even the adhesive force of the 1st adhesive bond layer 50 falls, it will be by external force. The pedestal can be easily separated from the semiconductor wafer.
Since the first adhesive layer 50 is formed in the peripheral portion 54 of the adhesive sheet 5 in the adhesive sheet 5, the first adhesive layer 50 is dissolved by a solvent, or physically cut by a cutter or a laser. And it is easy to reduce the adhesive force of the 1st adhesive bond layer 50, and it is easy to isolate | separate a base from a semiconductor wafer.

In the adhesive sheet 5, the central portion 53 inside the peripheral portion 54 is formed by stacking the first adhesive layer 50 and the second layer 51. The semiconductor wafer or the pedestal can be firmly fixed on the surface where only the first adhesive layer 50 is exposed. Further, since the central portion 53 is formed by stacking the first adhesive layer 50 and the second layer 51, the central portion 53 is more than the peripheral portion 54 formed by only the first adhesive layer 50. However, the adhesive strength is relatively low. Therefore, the base can be easily separated from the semiconductor wafer by an external force if the adhesive force of the peripheral portion 54 is reduced at least. Further, when the second layer 51 is in contact with the pedestal, the adhesive sheet 5 is easily peeled off from the pedestal, the adhesive residue is small, and the pedestal is easy to reuse.

The thickness of the adhesive sheet 5 is not specifically limited, For example, it is 10 micrometers or more, Preferably it is 50 micrometers or more. When the thickness is 10 μm or more, the unevenness on the surface of the semiconductor wafer device can be followed, and the adhesive sheet can be filled without a gap. Moreover, the thickness of the adhesive sheet 5 is 500 micrometers or less, for example, Preferably it is 300 micrometers or less. When the thickness is 500 μm or less, variation in thickness and shrinkage / expansion during heating can be suppressed or prevented.

Although the thickness of the 1st adhesive bond layer 50 in the center part 53 can be set suitably, Preferably it is 0.1 micrometer or more, More preferably, it is 0.5 micrometer or more, More preferably, it is 1 micrometer or more. Moreover, this thickness becomes like this. Preferably it is 300 micrometers or less, More preferably, it is 200 micrometers or less.
Further, the thickness of the second layer 51 in the central portion 53 can be set as appropriate.

Since the first adhesive layer generally has a lower elastic modulus than the second layer, undulation is likely to occur on the surface during formation. From such a viewpoint, it is preferable to make the first adhesive layer thinner and the second layer thicker. On the other hand, since the first adhesive layer generally has a higher glass transition temperature than the second layer, the shrinkage during formation is large. From such a viewpoint, it is preferable to make the first adhesive layer thick and the second layer thin.

FIG. 2 is a plan view of the adhesive sheet 5 of the first embodiment. As shown in FIG. 2, the adhesive sheet 5 has a circular shape when viewed in plan.
The diameter of the adhesive sheet 5 is not particularly limited. For example, the diameter of the adhesive sheet 5 is preferably +1.0 to −1.0 mm with respect to the diameter of the pedestal.

Further, when the adhesive sheet 5 is viewed in plan, the shape of the second layer 51 is circular. The area of the second layer 51 when the adhesive sheet 5 is viewed in plan is preferably 10% or more, more preferably 20% or more with respect to the area of the adhesive sheet 5 when the adhesive sheet 5 is viewed in plan. Preferably it is 50% or more. When it is 10% or more, the adhesive force of the first adhesive layer 50 formed on the peripheral portion 54 is likely to be reduced, and the pedestal is easily separated from the semiconductor wafer. The area of the second layer 51 is preferably 99.95% or less, more preferably 99.9% or less. A semiconductor wafer can be firmly fixed to a base as it is 99.95% or less.

The adhesive sheet of the present invention is not limited to the adhesive sheet 5 of the first embodiment. FIG. 3 is a schematic cross-sectional view of the adhesive sheet of the second embodiment. As shown in FIG. 3, in the adhesive sheet 6, the peripheral portion 64 is formed by the first adhesive layer 60, and the central portion 63 inside the peripheral portion 64 is formed by the second layer 61. . The adhesive force of the second layer 61 is lower than the adhesive force of the first adhesive layer 60.

In the adhesive sheet 6, a central portion 63 inside the peripheral portion 64 is formed by the second layer 61. Since the central portion 63 is formed of the second layer 61, if the adhesive force of the first adhesive layer 60 in the peripheral portion 64 is reduced, the pedestal can be easily separated from the semiconductor wafer by an external force. Further, since the second layer 61 is in contact with the pedestal, the adhesive sheet 6 is easily peeled off from the pedestal, the adhesive residue is small, and the pedestal is easy to reuse.

The thickness of the adhesive sheet 6 is not specifically limited, For example, it is the same as that of the adhesive sheet 5 of Embodiment 1.

FIG. 4 is a plan view of the adhesive sheet 6 according to the second embodiment. As shown in FIG. 4, the adhesive sheet 6 has a circular shape when viewed in plan. The diameter of the adhesive sheet 6 is not specifically limited, For example, it is the same as that of what was illustrated by the adhesive sheet 5 of Embodiment 1. FIG. Further, the area of the second layer 61 when the adhesive sheet 6 is viewed in plan is not particularly limited, and for example, is the same as that exemplified for the adhesive sheet 5 of the first embodiment.

The adhesive force of the second layers 51 and 61 is not particularly limited as long as it is lower than the adhesive force of the first adhesive layers 50 and 60. The adhesive strength of the second layers 51 and 61 is preferably such that, for example, the 90 ° peel peeling force for a silicon wafer under the conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min is less than 0.30 N / 20 mm. More preferably, it is 0.20 N / 20 mm or less. If it is less than 0.30 N / 20 mm, the second layers 51 and 61 can be easily peeled off. The lower limit of the 90 ° peel strength is not particularly limited, and is, for example, 0 N / 20 mm or more, preferably 0.001 N / 20 mm or more. The lower the 90 ° peel peel force, the easier the second layers 51 and 61 are peeled.

The adhesive strength of the first adhesive layers 50 and 60 is, for example, that the 90 ° peel peel force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peel speed of 300 mm / min is 0.30 N / 20 mm or more. Is preferable, and 0.40 N / 20 mm or more is more preferable. When it is 0.30 N / 20 mm or more, the semiconductor wafer can be favorably held on the pedestal, and back grinding and the like can be favorably performed. The upper limit of the 90 ° peel peel force is not particularly limited and is preferably as large as possible. For example, it is 30 N / 20 mm or less, preferably 20 N / 20 mm or less.

As shown in FIGS. 5 and 6, the adhesive sheet of the present invention may have other layers formed thereon. 5 and 6 are schematic cross-sectional views of an adhesive sheet including a third layer. In the adhesive sheet 5 of FIG. 5, a third layer 55 is formed across the peripheral portion 54 and the central portion 53. In the adhesive sheet 6 of FIG. 6, a third layer 65 is formed across the peripheral portion 64 and the central portion 63. Adhesive sheet with the third layers 55 and 65 from the semiconductor wafer by affixing the surface on which the third layers 55 and 65 having lower adhesive strength than the first adhesive layers 50 and 60 are exposed to the semiconductor wafer. 5 and 6 can be easily peeled off. Further, the adhesive residue on the semiconductor wafer can be eliminated, and the semiconductor wafer cleaning step can be omitted.

The adhesive force of the third layers 55 and 65 is not particularly limited as long as it is lower than the adhesive force of the first adhesive layers 50 and 60. For example, the 90 ° peel peeling force for a silicon wafer under conditions of a temperature of 23 ± 2 ° C. and a peeling speed of 300 mm / min is preferably less than 0.30 N / 20 mm, and preferably 0.20 N / 20 mm or less. More preferred. When the thickness is less than 0.30 N / 20 mm, the adhesive can be peeled without residue, and the semiconductor wafer cleaning process can be omitted. Moreover, the minimum of this 90 degree peeling force is not specifically limited, For example, it is 0 N / 20mm or more, Preferably it is 0.001 N / 20mm or more. A semiconductor wafer can be favorably hold | maintained to a base as it is 0 N / 20mm or more.

As long as it selects so that the adhesive force of the 1st adhesive bond layers 50 and 60 may become higher than the adhesive force of the 2nd layers 51 and 61 as an adhesive composition which comprises the 1st adhesive bond layers 50 and 60. There is no particular limitation.

As the adhesive composition constituting the first adhesive layers 50 and 60, a polyimide resin having an imide group and having a structural unit derived from a diamine having an ether structure at least partially can be used. Moreover, a silicone resin can also be used suitably. Especially, the said polyimide resin is preferable from the point of heat resistance, chemical resistance, and adhesive residue.

The polyimide resin can be generally obtained by imidizing (dehydrating and condensing) a polyamic acid that is a precursor thereof. As a method for imidizing the polyamic acid, for example, a conventionally known heat imidization method, azeotropic dehydration method, chemical imidization method and the like can be employed. Of these, the heating imidization method is preferable. When the heat imidization method is employed, it is preferable to perform heat treatment under a nitrogen atmosphere or an inert atmosphere such as a vacuum in order to prevent deterioration of the polyimide resin due to oxidation.

The polyamic acid is charged in an appropriately selected solvent such that an acid anhydride and a diamine (including both a diamine having an ether structure and a diamine not having an ether structure) have a substantially equimolar ratio. Can be obtained by reaction.

The diamine having an ether structure is not particularly limited as long as it is a compound having an ether structure and having at least two terminals having an amine structure. Examples thereof include diamine having a glycol skeleton.

Examples of the diamine having a glycol skeleton include a polypropylene glycol structure and a diamine having one amino group at each end, a polyethylene glycol structure, and one amino group at each end. Examples thereof include a diamine having a polytetramethylene glycol structure and a diamine having an alkylene glycol such as a diamine having one amino group at each end. Moreover, the diamine which has two or more of these glycol structures and has one amino group in both the ends can be mentioned.

The molecular weight of the diamine having an ether structure is preferably in the range of 100 to 5000, and more preferably 150 to 4800. When the molecular weight of the diamine having an ether structure is in the range of 100 to 5,000, the first adhesive layers 50 and 60 having high adhesive strength at low temperatures and exhibiting peelability at high temperatures are easily obtained.

In the formation of the polyimide resin, a diamine having no ether structure can be used in combination with a diamine having an ether structure. Examples of the diamine having no ether structure include aliphatic diamines and aromatic diamines. By using a diamine having no ether structure in combination, the adhesion with the adherend can be controlled. The mixing ratio of the diamine having an ether structure and the diamine having no ether structure is preferably in the range of 100: 0 to 10:90, more preferably 100: 0 to 20: in terms of molar ratio. 80, more preferably 99: 1 to 30:70. When the mixing ratio of the diamine having an ether structure and the diamine having no ether structure is within a range of 100: 0 to 10:90 in terms of molar ratio, the thermal peelability at a high temperature is excellent.

Examples of the aliphatic diamine include ethylenediamine, hexamethylenediamine, 1,8-diaminooctane, 1,10-diaminodecane, 1,12-diaminododecane, 4,9-dioxa-1,12-diaminododecane, , 3-bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane (α, ω-bisaminopropyltetramethyldisiloxane) and the like. The molecular weight of the aliphatic diamine is usually 50 to 1,000,000, preferably 100 to 30,000.

Examples of the aromatic diamine include 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, and 4,4′-diaminodiphenylpropane. 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) -2,2- Dimethylpropane, 4,4'-diaminobenzophenone, etc. It is. The molecular weight of the aromatic diamine is usually 50 to 1000, preferably 100 to 500. The molecular weight of the aliphatic diamine and the molecular weight of the aromatic diamine are values measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene (weight average molecular weight).

Examples of the acid anhydride include 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 2,2-bis (2, 3-dicarboxyphenyl) hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), bis (2,3-dicarboxyphenyl) methane dianhydride Bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfone Anhydride, pyromellitic dianhydride, ethylene glycol bis trimellitic dianhydride and the like. These may be used alone or in combination of two or more.

Examples of the solvent for reacting the acid anhydride with the diamine include N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, and cyclopentanone. These may be used alone or in combination. Further, in order to adjust the solubility of raw materials and resins, a nonpolar solvent such as toluene or xylene may be appropriately mixed and used.

Examples of the silicone resin include peroxide cross-linked silicone pressure-sensitive adhesives, addition reaction type silicone pressure-sensitive adhesives, dehydrogenation reaction type silicone pressure-sensitive adhesives, and moisture-curing type silicone pressure-sensitive adhesives. The said silicone resin may be used individually by 1 type, and may use 2 or more types together. When the silicone resin is used, the heat resistance becomes high, and the storage elastic modulus and adhesive strength at high temperatures can be appropriate values. Among the silicone resins, addition reaction type silicone pressure-sensitive adhesives are preferable in terms of few impurities.

The adhesive composition constituting the first adhesive layers 50 and 60 may contain other additives. Examples of such other additives include flame retardants, silane coupling agents, and ion trapping agents. Examples of the flame retardant include antimony trioxide, antimony pentoxide, and brominated epoxy resin. Examples of the silane coupling agent include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like. Examples of the ion trapping agent include hydrotalcites and bismuth hydroxide. Such other additives may be only one kind or two or more kinds.

The material constituting the second layers 51 and 61 is not particularly limited as long as the second layers 51 and 61 are selected so that the adhesive strength of the second layers 51 and 61 is lower than the adhesive strength of the first adhesive layers 50 and 60. . Examples of the material constituting the second layers 51 and 61 include inorganic materials such as Cu, Cr, Ni, and Ti. Moreover, the above-mentioned polyimide resin and the above-mentioned silicone resin can also be used.

The material constituting the third layers 55 and 65 is not particularly limited as long as the adhesive force of the third layers 55 and 65 is selected to be lower than the adhesive force of the first adhesive layers 50 and 60. For example, the same layer as the second layers 51 and 61 can be used.

(Manufacture of adhesive sheets)
The adhesive sheet 5 is produced as follows, for example. First, a solution containing a material for forming the second layer 51 is prepared. Next, the solution is applied to a base material so as to have a predetermined thickness to form a coating film, and then the coating film is dried under predetermined conditions to form the second layer 51. Examples of the base material include metal foil such as SUS304, 6-4 alloy, aluminum foil, copper foil, Ni foil, polyethylene terephthalate (PET), polyethylene, polypropylene, fluorine-based release agent, and long-chain alkyl acrylate release agent. A plastic film, paper, or the like whose surface is coated with a release agent such as, can be used. Moreover, it does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, spin coat coating etc. are mentioned.

Next, by punching or the like from the second layer 51 side, punching into a predetermined shape (for example, circular, rectangular, etc.), leaving a punched portion (second layer 51 of circular shape, rectangular shape, etc.) Remove the outside.

On the other hand, a solution containing a composition for forming the first adhesive layer 50 is prepared.

Next, a solution containing a composition for forming the first adhesive layer 50 is formed on the substrate on which the second layer 51 punched into a predetermined shape is laminated. A coating film is formed by coating from the side 51 to a predetermined thickness. Thereafter, the coating film is dried under predetermined conditions to form the first adhesive layer 50. From the above, the adhesive sheet 5 shown in FIGS. Note that the adhesive sheet 6 shown in FIGS. 3 and 4 can be formed by a method substantially similar to that of the adhesive sheet 5.

The third layers 55 and 65 shown in FIGS. 5 and 6 can be formed by the same method as the second layer 51.

In the above description, the adhesive sheets 5 and 6 having a circular shape when viewed in plan have been described. However, the shape is not particularly limited, and may be another shape such as a polygon or an ellipse.

In addition, the adhesive sheets 5 and 6 in which the shapes of the second layers 51 and 61 are circular when viewed in plan have been described. However, the shape is not particularly limited, and may be another shape such as a polygon or an ellipse.

The adhesive sheet for manufacturing a semiconductor device of the present invention is used for fixing a semiconductor wafer to a pedestal. Specifically, it can be suitably used in a semiconductor device manufacturing method described later.

[Method for Manufacturing Semiconductor Device]
The manufacturing method of the semiconductor device of this invention includes the process of fixing a semiconductor wafer to a base using an adhesive sheet, and the process of isolate | separating a base from a semiconductor wafer. For example, there is a method including a step of fixing a semiconductor wafer to a pedestal using an adhesive sheet, a step of back grinding the semiconductor wafer, and a step of separating the pedestal from the back-ground semiconductor wafer.

In the following description, the case where the adhesive sheet 5 of Embodiment 1 is used will be described. FIG. 7 is a schematic diagram illustrating a state in which the semiconductor wafer is fixed to the pedestal using the adhesive sheet of the first embodiment.

First, a process of fixing the semiconductor wafer 3 to the base 1 using the adhesive sheet 5 is performed. Specifically, the surface of the adhesive sheet 5 on which the first adhesive layer 50 and the second layer 51 are exposed is attached to the base 1, and only the first adhesive layer 50 of the adhesive sheet 5 is exposed. The surface is attached to the circuit forming surface of the semiconductor wafer 3.

The semiconductor wafer 3 is not particularly limited, and examples thereof include a germanium wafer, a gallium-arsenic wafer, a gallium-phosphorus wafer, a gallium-arsenic-aluminum wafer, and a compound semiconductor wafer such as a sapphire wafer. Among these, a silicon wafer is preferable.

A semiconductor wafer 3 having a circuit forming surface and a non-circuit forming surface is used. Moreover, what has a silicon penetration electrode (through-silicon via) can be used conveniently. This is because a silicon wafer having through silicon vias is usually thinned by back grinding, which will be described later, so that it is desirable to fix the silicon wafer to the pedestal 1 and reinforce the strength.

Although the thickness of the semiconductor wafer 3 is not specifically limited, For example, it is 400-1200 micrometers, Preferably it is 450-1000 micrometers.

Although the diameter of the semiconductor wafer 3 is not specifically limited, For example, it is 75-450 mm. As such a semiconductor wafer 3, a commercially available 200 mm wafer, 300 mm wafer, or the like can be used.

The pedestal 1 is not particularly limited, and examples thereof include compound wafers such as silicon wafers, SiC wafers, and GaAs wafers, glass wafers, metal foils such as SUS, 6-4 Alloy, Ni foil, and Al foil. In the case of adopting a round shape in plan view, a silicon wafer or a glass wafer is preferable. Moreover, when it is a rectangle by planar view, a SUS board or a glass plate is preferable.

Moreover, as the base 1, for example, low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, polymethylpentene, etc. Polyolefin, ethylene-vinyl acetate copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene -Hexene copolymers, polyesters such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamide Polyphenyl sulphates id, aramid (paper), can be glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, also possible to use paper or the like.

The pedestal 1 may be used alone or in combination of two or more. Although the thickness of the base 1 is not specifically limited, For example, it is about 10 micrometers-about 20 mm normally.

Although the diameter of the base 1 is not specifically limited, For example, it is 100-450 mm. As such a pedestal 1, a commercially available 200 mm wafer, 300 mm wafer, or the like can be used.

The method of attaching (fixing) is not particularly limited, but pressure bonding is preferable. The crimping is usually performed while pressing with a pressing means such as a crimping roll. As conditions for pressure bonding, for example, 20 to 300 ° C., 0.001 to 10 MPa, and 0.001 to 10 mm / sec are preferable. The crimping time is usually 0.1 to 10 minutes.
After the pressure bonding, the first adhesive layer 50 and the second layer 51 are imidized as necessary. Thereby, the semiconductor wafer 3 can be favorably fixed to the base 1. Imidization can be performed by a conventionally known method, for example, it can be imidized under conditions of 150 to 500 ° C. and 0.5 to 5 hours. Only one of the first adhesive layer 50 and the second layer 51 may be imidized.

Next, the semiconductor wafer 3 is back-ground. The back grinding can be performed by a conventionally known method.

The thickness of the back-ground semiconductor wafer is, for example, 1 to 300 μm, and preferably 5 to 100 μm.

After the back grinding, the non-circuit forming surface (the back ground surface) of the semiconductor wafer 3 can be processed. Examples of processing methods include electrode formation, metal wiring formation, and protective film formation. Note that a through silicon via may be formed by the processing.

After back grinding and processing, the pedestal 1 is separated from the semiconductor wafer 3.

A method for separating the pedestal 1 from the semiconductor wafer 3 is not particularly limited, but it is preferable to separate the pedestal 1 after reducing the adhesive force of the first adhesive layer 50 in the peripheral portion 54. Thereby, it can isolate | separate easily. As a method of reducing the adhesive force of the first adhesive layer 50, a method of lowering the adhesive force by dissolving the first adhesive layer 50 with a solvent, a physical method using a cutter, a laser, or the like is applied to the first adhesive layer 50. Examples thereof include a method of reducing the adhesive force by cutting a slit, a method of forming the first adhesive layer 50 with a material whose adhesive force is reduced by heating, and a method of reducing the adhesive force by heating.

In the above description, as a method of fixing the semiconductor wafer 3 to the pedestal 1 using the adhesive sheet 5, the surfaces of the adhesive sheet 5 on which the first adhesive layer 50 and the second layer 51 are exposed are pasted on the pedestal 1. The method of attaching the surface of the adhesive sheet 5 where only the first adhesive layer 50 is exposed to the circuit forming surface of the semiconductor wafer 3 has been described. However, the method of fixing the semiconductor wafer 3 to the pedestal 1 using the adhesive sheet 5 is not particularly limited, and the surface of the adhesive sheet 5 on which only the first adhesive layer 50 is exposed is attached to the pedestal 1 and the adhesive sheet 5 may be a method in which the surface on which the first adhesive layer 50 and the second layer 51 are exposed is attached to the circuit forming surface of the semiconductor wafer 3.

Further, the case where the semiconductor wafer 3 having a circuit forming surface and a non-circuit forming surface is used has been described. However, the present invention is not limited to those having a circuit forming surface and a non-circuit forming surface, and both surfaces may be non-circuit forming surfaces.

Further, the case where the semiconductor wafer 3 fixed to the base 1 is back-ground has been described. However, back grinding is not essential, and the semiconductor wafer 3 may be processed without back grinding.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to a following example, unless the summary is exceeded.

The components used in the examples will be described.
PMDA: pyromellitic dianhydride (molecular weight: 218.1)
DDE: 4,4′-diaminodiphenyl ether (molecular weight: 200.2)
D-4000: Heinzmann polyether diamine (molecular weight: 4023.5)
DMAc: N, N-dimethylacetamide NMP: N-methyl-2-pyrrolidone D-2000: polyether diamine manufactured by Heinzmann (molecular weight: 1990.8)
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride PPD: p-phenylenediamine separator (long polyester film treated on one side with a silicone-based release agent: thickness 38 μm)
Long polyester film (thickness 25μm)

An adhesive sheet was produced by the following method.

Examples 1 and 5
<Preparation of First Adhesive Layer Solution and Second Layer Solution>
In an atmosphere under a nitrogen stream, D-4000 258.25 g, DDE 78.95 g, and PMDA 100 g were mixed and reacted at 929.05 g of DMAc at 70 ° C. to obtain a first adhesive layer solution (polyamide). An acid solution A) was obtained. The resulting first adhesive layer solution was cooled to room temperature (23 ° C.).
A second layer solution (polyamic acid solution B) was obtained in the same manner as the first adhesive layer solution except that the formulation in Table 1 was followed. The resulting second layer solution was cooled to room temperature (23 ° C.).
<Production of circular sheet>
The second layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having the second layer.
A long polyester film is laminated on the second layer of the obtained sheet, half-cut with a Thomson mold to a diameter of 198 mm, and the outer part is left, leaving the punched part (the inner part punched with the Thomson mold). Removal gave a circular sheet. In addition, said half cut means the cut in the aspect which cuts a polyester film and a 2nd layer completely, and does not cut a separator completely (cut to the middle of a separator).
<Preparation of adhesive sheet>
The polyester film of the circular sheet was peeled off, and the first adhesive layer solution was applied on the second layer of the circular sheet so as to have a diameter of 200 mm or more, and dried at 90 ° C. for 3 minutes. A long polyester film was laminated on the dried first adhesive layer to obtain an adhesive sheet having the shape of Embodiment 1 shown in FIGS.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 100 μm. The diameter of the second layer was 198 mm, and the thickness of the second layer was 2 μm. The thickness of the 1st adhesive bond layer in the center part of an adhesive sheet was 98 micrometers.

Example 2
<Preparation of first adhesive layer solution>
A first adhesive layer solution was obtained in the same manner as in Example 1 except that the composition according to Table 1 was followed.
<Preparation of adhesive sheet>
On the SUS foil (Toyo Seikan Co., Ltd., SUS 304H-TA), Cu plating with a copper sulfate plating bath was performed so that the Cu film thickness was 0.5 μm to obtain a SUS foil with Cu plating. The obtained Cu-plated SUS foil was cooled to room temperature (23 ° C.),
The 1st adhesive layer solution of the mixing | blending of Table 1 was apply | coated to SUS foil with Cu plating, and it was dried at 90 degreeC for 2 minutes. Next, the SUS foil was peeled to obtain a polyamic acid layer with Cu plating. Cu etching was performed on the obtained polyamic acid layer with Cu plating. As a result, a circular (195 mm diameter) Cu plated portion (second layer) was left, and the others were removed. From the above, an adhesive sheet having the shape of Embodiment 1 shown in FIGS.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 120 μm. The diameter of the second layer was 195 mm, and the thickness of the second layer was 0.5 μm. The thickness of the 1st adhesive bond layer in the center part of an adhesive sheet was 119.5 micrometers.
In Example 2, when the adhesive sheet is formed, a shape in which the second layer is formed on the first adhesive layer (a shape in which the first adhesive layer does not exist on the side surface side of the second layer). However, since the second layer is as thin as 0.5 μm, the first adhesive layer is as thick as 120 μm, and the first adhesive layer is relatively soft (low elastic modulus). Thus, the second layer is embedded in the first adhesive layer. Therefore, the adhesive sheet of Example 2 has the cross-sectional shape shown in FIG.

Example 3
An adhesive sheet was obtained in the same manner as in Example 1 except that the composition according to Table 1 was followed.

Example 4
<Production of circular sheet>
The second layer solution prepared in Example 1 was applied to a separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a second layer.
A long polyester film is laminated on the second layer of the obtained sheet, half-cut with a Thomson mold to a diameter of 198 mm, and the outer part is left, leaving the punched part (the inner part punched with the Thomson mold). Removal was performed to obtain a circular sheet (thickness: 200 μm).
<Preparation of adhesive sheet>
The first adhesive layer solution prepared in Example 1 was applied to a separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a first adhesive layer.
A long polyester film is laminated on the first adhesive layer of the obtained sheet, half-cut to 198 mm in diameter with a Thomson die, and the punched portion leaving the outside (inside punched with the Thomson die) Was removed to obtain a hollow sheet (thickness: 200 μm).
The separator of the circular sheet and the hollow sheet is peeled off and bonded so that the second layer of the circular sheet fits into the part where the first adhesive layer of the hollow sheet does not exist. An adhesive sheet having the shape of Embodiment 2 shown in FIG.
The entire adhesive sheet had a diameter of 200 mm and a thickness of 200 μm. The diameter of the second layer was 198 mm, and the thickness of the second layer was 200 μm.

Comparative Example 1
A single-layer adhesive sheet composed of the same first adhesive layer as in Example 1 was obtained. The adhesive sheet was circular and had a diameter of 200 mm and a thickness of 150 μm.

[Measurement of adhesive strength of first adhesive layer]
The first adhesive layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a first adhesive layer having a thickness of 20 μm.
The first adhesive layer of the obtained sheet was bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to obtain a first adhesive layer with a silicon wafer.
The first adhesive layer with a silicon wafer was processed to a width of 20 mm and a length of 100 mm, and a 90 ° peel evaluation was performed at a temperature of 23 ° C. and 300 mm / min using a tensile tester (manufactured by Shimadzu Corporation, Autograph AGS-H). went. The results are shown in Table 1.

[Measurement of adhesive strength of second layer]
The second layer solution was applied to the separator and dried at 90 ° C. for 3 minutes to obtain a sheet having a second layer having a thickness of 20 μm.
The second layer of the obtained sheet was bonded to an 8-inch silicon wafer and imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours to obtain a second layer with a silicon wafer.
A second layer with a silicon wafer is processed to a width of 20 mm and a length of 100 mm, and a 90 ° peel evaluation is performed at a temperature of 23 ° C. and 300 mm / min using a tensile tester (manufactured by Shimadzu Corp., Autograph AGS-H). It was. The results are shown in Table 1.
In addition, about the adhesive force of the 2nd layer of Example 2, 90 degree peel evaluation was performed using what bonded the 2nd layer to the 8-inch silicon wafer.

[Process resistance evaluation]
Examples 1-4
The surfaces on which the first adhesive layer and the second layer of the adhesive sheets of Examples 1 to 4 were exposed were attached to a pedestal (a silicon wafer having a diameter of 200 mm and a thickness of 726 μm). The pasting was performed by roll lamination at a temperature of 90 ° C. and a pressure of 0.1 MPa.
Next, the adhesive sheet surface of the adhesive sheet with a pedestal was attached to the circuit forming surface of a silicon wafer having a diameter of 200 mm and a thickness of 725 μm. The pasting was performed by roll lamination at a temperature of 90 ° C. and a pressure of 0.1 MPa. After pasting, the adhesive sheet was imidized in a nitrogen atmosphere at 300 ° C. for 1.5 hours. As a result, a laminated body in which the pedestal, the adhesive sheet, and the silicon wafer were sequentially laminated was obtained.
Backgrinding was performed using the obtained laminate, and the case where the silicon wafer could be sufficiently fixed in the backgrind and satisfactorily background could be obtained. As evaluated.
Example 5
The process resistance was evaluated in the same manner as in Examples 1 to 4, except that the surface exposed only by the first adhesive layer was attached to the pedestal.
Comparative Example 1
A laminate was obtained by the same method as in Examples 1 to 4, and the process resistance was evaluated.
The results are shown in Table 1.

[Peelability evaluation]
A laminated body in which a pedestal, an adhesive sheet, and a silicon wafer were sequentially laminated was obtained by the same method as in the process resistance evaluation.
Using a Thomson blade, a cut was made inward from the side surface of the adhesive sheet layer. The cut was made until the second layer was reached. After cutting, the silicon wafer was adsorbed upward using vacuum tweezers arranged on the upper side (silicon wafer side) of the laminate. The case where it was able to adsorb | suck was evaluated as (circle) and the case where it was not able to adsorb was evaluated as x. The results are shown in Table 1.

In Examples 1 to 5, the silicon wafer could be sufficiently fixed, and the back grinding could be performed satisfactorily. Moreover, the silicon wafer and the pedestal could be easily separated by cutting. On the other hand, Comparative Example 1 could not be peeled even when a cut was made in the adhesive sheet layer.

DESCRIPTION OF SYMBOLS 1 Base 3 Semiconductor wafer 5 Adhesive sheet 50 1st adhesive layer 51 2nd layer 53 Center part 54 Peripheral part 55 3rd layer 6 Adhesive sheet 60 1st adhesive layer 61 2nd layer 63 Central part 64 Peripheral part 65 third layer

Claims (6)

An adhesive sheet for manufacturing a semiconductor device used for fixing a semiconductor wafer to a pedestal,
A first adhesive layer and a second layer having an adhesive strength lower than that of the first adhesive layer;
An adhesive sheet for manufacturing a semiconductor device, wherein at least a peripheral portion of the adhesive sheet for manufacturing a semiconductor device is formed by the first adhesive layer. 2. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein a central part inside the peripheral part is formed by stacking the first adhesive layer and the second layer. 2. The adhesive sheet for manufacturing a semiconductor device according to claim 1, wherein a central portion inside the peripheral portion is formed by the second layer. 4. The semiconductor device manufacturing according to claim 1, wherein a third layer having an adhesive force lower than that of the first adhesive layer is formed across the peripheral portion and the central portion. Adhesive sheet. The semiconductor device obtained using the adhesive sheet for semiconductor device manufacture of any one of Claims 1-4. Fixing the semiconductor wafer to the pedestal using the adhesive sheet for manufacturing a semiconductor device according to claim 1;
And a step of separating the pedestal from the semiconductor wafer.

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